Typical uOne Call Flows 365
protocols: POP3, IMAP4, or HTTP. The following steps summarize how the client retrieves
a message:
Step 1 Queries DNS to find the IP address of the server.
Step 2 Establishes a TCP/IP connection to the server.
Step 3 Optionally establishes an SSL connection to the server.
Step 4 Establishes a POP3, IMAP4, or HTTP connection to the server to retrieve
the message.
uOne uses IMAP4 for storage and retrieval of messages from the messaging server.
A typical IMAP session is summarized in Figure 9-4.
Figure 9-4 IMAP session.
Typical uOne Call Flows
This section discusses the following typical uOne call flows:
Subscriber does not answer call.
Caller leaves a message for a subscriber.
Subscriber is notified to retrieve messages.
Connect
Service ready
Login
Login complete
Select
Select response
Select complete
ServerClient
Fetch
Fetch response
Fetch complete
Logout
Bye
366 Chapter 9: Unified Messaging
Subscriber calls the UM server to retrieve messages.
Inbound fax message to a subscriber.
Printing a fax message from a subscriber’s mailbox to an alternate fax number.
Overall uOne protocol flow sequence.
Subscriber Does Not Answer Call
When someone calls a subscriber and there is no answer, the call is forwarded to the
gateserver. When the local exchange carrier (LEC) switch detects an incoming call that is
destined for a busy or non-answering party, the switch formulates a Q.931 setup message
with the redirected number (RDN) field set to the original destination number, and sends it
to the gateway. The called-party number of the setup message is set to one of the DNIS
access numbers of the gateway. The original called number is then the RDN, and the
number that was called to access the server is the DNIS. Whenever the RDN field is
populated, the UM application uses it to retrieve (using LDAP) the subscriber’s profile from
a directory server. If there is a matching subscriber, UM retrieves and plays the subscriber’s
personal greeting. Figure 9-5 shows an example of how this process works.
Figure 9-5 Retrieve subscriber’s personal greeting.
In this example, the presence of RDN indicates a call to the subscriber. The UM searches
for the subscriber profile using 6018881234, retrieves it, and plays the personal greeting.
When a subscriber calls the UM server to access messages, automatic number identification
(ANI) is set to the calling number, DNIS is set to the called number, and RDN is not
populated. In this case, UM plays the general welcome message and requests the caller’s
phone number and PIN. A subscriber calling from his or her own phone can simply press
the # key, in which case UM uses the ANI to retrieve the subscriber’s profile, as shown in
Figure 9-6.
Calling number
6019991234
Access number
6017771234
ANI=6019991234
DNIS=6017771234
RDN=6018881234
UM Server
H.323 Gateway
LEC switch
Call forward
on busy or
ring no answer
Called number
6018881234
PRI
IP
Typical uOne Call Flows 367
Figure 9-6 ANI profile retrieval.
In this example, an unpopulated RDN field indicates a call from the subscriber to retrieve
messages. The UM requests that the subscriber enter his or her phone number or simply
press #. If the subscriber enters a phone number, it is used in a directory search (LDAP). If
the subscriber enters #, 6016661234 is used to search the directory for his or her profile.
Caller Leaves a Message for a Subscriber
When someone calls a subscriber’s phone number and does not get an answer, the
subscriber’s switch forwards the call to the Cisco AS5300 gateway. Figure 9-7 shows how
the messaging server accepts and routes a message to the subscriber.
Figure 9-7 User calls and leaves a message.
Calling number
6016661234
Access number
6017771234
ANI=6016661234
DNIS=6017771234
RDN=
UM Server
H.323 Gateway
LEC switch
PRI
IP
9
14
12
17
19
Disk store
1
Q.931 H.323
3
DS Routing table
16 178
2
15 181374
9
1
PSTN
15 181376
Agent Monitor Manager
10 LDAP20 SMTP
5
Schedule table
IMAP 11
Messaging
Server
UM Agent
Directory
Server
Call/Media Agent

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